RFR (M): 8003853: specify offset of IC load in java_to_interp stub

[Christian Thalinger]

The change looks good.  I have some minor comments though:
src/share/vm/code/compiledIC.hpp:

+  static uint to_interp_stub_size();
+  static uint reloc_to_interp_stub();
+            stub_size  += CompiledStaticCall::to_interp_stub_size();
+            reloc_size += CompiledStaticCall::reloc_to_interp_stub();
stub_size and reloc_size are ints.  We should change the return type from uint to int.

src/cpu/x86/vm/compiledIC_x86.cpp:
 108 uint CompiledStaticCall::to_interp_stub_size() {
 109   return 10              // movl; jmp
 110          LP64_ONLY(+5);  // movq (1+1+8); jmp (1+4)
 111 }
In expectancy of future changes we should do:
 108 uint CompiledStaticCall::to_interp_stub_size() {
 109   return NOT_LP64(10)    // movl; jmp
 110          LP64_ONLY(15);  // movq (1+1+8); jmp (1+4)
 111 }
And one question unrelated to this change (because it was there before):

src/cpu/sparc/vm/compiledIC_sparc.cpp:
 126 // Relocation entries for call stub, compiled java to interpreter.
 127 uint CompiledStaticCall::reloc_to_interp_stub() {
 128   return 10;  // 4 in emit_java_to_interp + 1 in Java_Static_Call
 129 }
Why does it say 5 relocations but returns 10?

Did someone try a Zero build?

-- Chris

On Apr 23, 2013, at 1:09 AM, "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com> wrote:

> Hi all,
>  
> In the java_to_interp stub of CompiledStaticCalls one relocation is used to find
> two code locations:
> -          the beginning of the stub
> -          the IC load instruction.
> On x86 and sparc, the IC load instruction is the first instruction of the stub,
> thus both locations have the same address.
> On PPC, the IC load instruction is not the first instruction in the stub, thus
> we must add an offset to the relocation to access it.
>  
> As the manipulation of  CompiledStaticCalls is in shared code, we would have
> to introduce platform dependencies there.
>  
> This change moves the platform dependent code from CompiledStaticCall
> to a new file compiledIC_<cpu>.cpp.  It also moves the code issuing the
> stub from the ad file to this new file into the class CompiledStaticCall.
> This removes redundancies between x86_64.ad and x86_32.ad.  Also,
> ‘extern’ declarations in compile.cpp can be replaced by properly typed
> Calls to methods in CompiledStaticCall.
>  
> Dean Long ran this change through JPRT with status OK (thanks!).
>  
> Please review and push this change.
> http://cr.openjdk.java.net/~goetz/webrevs/8003853-3/
>  
> Best regards,
>   Goetz Lindenmaier

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